双层柱面网壳随机风致响应研究

发布时间：2018-04-24 13:20

本文选题：背景响应 + 共振响应　；参考：《东南大学》2015年硕士论文

【摘要】：大跨屋盖结构具有造型优美,力学性能良好的特点,近些年来广泛应用于各类建筑中,但目前我国规范只有针对高耸建筑的风振计算,并没有大跨屋盖的风振计算。本文以双层柱面网壳为研究背景,在理论上对网壳风振响应机理、计算方法进行了一系列研究。本文的主要研究工作如下：1.比较频域内风振响应的两种计算方法。分别计算背景响应、共振响应,然后叠加得到总响应的结果,与采用自适应Simpson算法直接计算得到的结果是一致的。不同模态下的共振响应与背景响应的比例,随着模态阶数升高而减小。低阶模态以共振响应为主,高阶模态以背景响应为主。2.振型截取研究。结构整体背景响应可以通过静力分析得到,通过振型叠加法可以获得不同模态下的背景响应。在总结整体背景响应、振型背景响应的基础上,提出背景响应的振型能量参与系数计算方法,由振型能量参与系数获得累积振型能量参与系数。通过累积振型能量参与系数,判断所选振型是否合理。对于双层柱面网壳结构,取前20阶模态便可满足需求。3.时域和频域一致性研究。利用线性滤波法模拟出脉动风速时程,并进行统计检验：利用脉动风速时程,得出脉动风力时程,在Ansys中进行时程分析,获得各点的位移响应根方差。振型组合采用CQC法和时域计算结果吻合,振型组合采用SRSS法和时域结果有一定误差。4.风致响应影响因素研究。利用频域分析方法,分别对模态耦合项、脉动风速谱、空间相干函数、地面粗糙度、体型系数、基本风压、阻尼比进行研究。研究表明：模态耦合项、空间相干函数对位移响应向量空间分布有影响；体型系数对位移响应较小；地面粗糙度、基本风压、阻尼比只影响位移响应的幅值。5.脉动风等效静力风荷载和风振系数研究。介绍了改进LRC法计算等效静力风荷载原理。通过分析,改进LRC法计算得出的指定节点的峰值位移和CQC方法的计算结果吻合的非常好,误差在6%以内。通过对三个算例的竖向位移风振系数分析,发现在整体上竖向位移风振系数分布较平缓,离散较小；位移风振系数最大值和最小值差距较小。
[Abstract]:The long-span roof structure has the characteristics of beautiful shape and good mechanical performance. In recent years, it has been widely used in all kinds of buildings. But at present, the code of our country only calculates the wind-induced vibration of high-rise buildings, and does not calculate the wind-induced vibration of large-span roof. In this paper, the wind-induced response mechanism and calculation method of double-layer cylindrical reticulated shell are studied in theory. The main research work of this paper is as follows: 1. Two methods for calculating wind vibration response in frequency domain are compared. The results of background response and resonance response are calculated respectively, and then the total response is obtained by superposition, which is consistent with the results obtained by direct calculation using adaptive Simpson algorithm. The ratio of resonance response to background response in different modes decreases with the increase of modal order. The resonance response is dominant in the low order mode and the background response in the higher order mode. Study on mode interception. The whole background response of the structure can be obtained by static analysis, and the background response under different modes can be obtained by the mode superposition method. On the basis of summing up the whole background response and the mode background response, the calculation method of the mode energy participation coefficient of the background response is put forward, and the cumulative mode energy participation coefficient is obtained from the mode energy participation coefficient. Whether the selected mode is reasonable or not is judged by accumulative energy participation coefficient. For double layer cylindrical reticulated shell structure, the first 20 order modes can meet the demand. 3. Research on time domain and frequency domain consistency. The time history of pulsating wind speed is simulated by linear filtering method, and the statistical test is carried out. By using the time history of pulsating wind speed, the pulsating wind time history is obtained, and the root variance of displacement response at each point is obtained by time history analysis in Ansys. The results of mode combination using CQC method and time domain calculation are in agreement with the results of time domain calculation. The results of mode combination using SRSS method and time domain results have a certain error. 4. Study on the influencing factors of Wind-induced response. The modal coupling term, pulsating wind speed spectrum, spatial coherence function, ground roughness, shape coefficient, basic wind pressure and damping ratio are studied by frequency domain analysis method. The results show that the spatial coherence function has an effect on the spatial distribution of the displacement response vector, the shape coefficient has little effect on the displacement response, and the roughness of the ground, the basic wind pressure and the damping ratio only affect the amplitude of the displacement response. Study on equivalent static wind load and wind vibration coefficient of pulsating wind. The principle of calculating equivalent static wind load by improved LRC method is introduced. Through analysis, the peak displacement calculated by improved LRC method is in good agreement with that of CQC method, and the error is less than 6%. Through the analysis of the vertical displacement wind vibration coefficient of three examples, it is found that the vertical displacement wind vibration coefficient distributes slowly and discretely on the whole, and the difference between the maximum and the minimum value of the displacement wind vibration coefficient is small.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU399;TU311.3

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